Consolidate ICHI Liquidity

Proposal is to:

1. Create a new ICHI-ETH pool on Sushiswap
2. Set rewards for the new ICHI-ETH pool to 50% of the total
3. Split remaining 50% of total rewards between stablecoin pools Rationale:
4. Sunset all existing ICHI pools (ICHI-ETH, oneETH-ICHI, ICHI-oneBTC, ICHI-ETH Uniswap)

Having liquidity fragmented between 4 pools is counter-productive, and joining them is the obvious solution. The choice of Sushiswap is because they are innovating at a much faster pace than Uniswap thanks to their merger with Yearn, and in order to get ICHI-ETH added to their Onsen program for extra rewards.